QUASI-ELASTIC NEUTRINO SCATTERING FROM OXYGEN AND THE ATMOSPHERIC NEUTRINO PROBLEM

We examine several phenomena beyond the scope of Fermi-gas models that affect the quasielastic scattering (from oxygen) of neutrinos in the 0.1-3.0 GeV range. These include Coulomb interactions of outgoing protons and leptons, a realistic finite-volume mean field, and the residual nucleon-nucleon interaction. None of these effects are accurately represented in the Monte Carlo simulations used to predict event rates due to mu and e neutrinos from cosmic-ray collisions in the atmosphere. We nevertheless conclude that the neglected physics cannot account for the anomalous mu-to-e ratio observed at Kamiokande and IMB, and is unlikely to change absolute event rates by more than 10-15 %. We briefly.mention other phenomena, still to be investigated in detail, that may produce larger changes.